The development of wireless networking has provided mobility to users while allowing them to remain in contact with others such as professional associates and family members. As the capacity and coverage of these systems have increased, the types and quantity of services being implemented has also increased. These services include communication modes, data applications, messaging applications, and the like. The increasing availability of services and applications has driven continued enhancements in mobile device design. For example, WLANs were originally primarily used by computing devices, such as laptop computers. WLANs have since evolved to support voice communication in addition to applications and services that require high speed broadband service such as streaming video. Today, it is increasingly common for mobile communication devices to include means for accessing WLANs in addition to traditional mobile cellular networks. As a result, there has been substantial overlap in the range of services and applications used among mobile communication devices and more conventional portable computing devices.
One service that is gaining widespread popularity on mobile communication devices is instant messaging (IM). Instant messaging can be more useful than short message service (SMS) messaging, sometimes referred to as “texting,” and its multimedia counterpart, media messaging service (MMS). SMS and MMS allow users to send messages to other users, but with no assurance that the target of the message is presently available. Instant messaging, on the other hand, typically maintains presence information for each IM user so that other users can be informed of the presence state of other users of interest to them.
A conventional IM system uses an IM server which maintains presence information for all subscribing users. Presence of a user can be identified, for example, as “offline,” “busy,” “available,” and on the like. An IM client application on the user's device interacts with the IM server to keep the IM server's presence information current, which typically involves the IM server frequently verifying each user's presence status by sending handshake messages. This constant handshaking occurs between the IM client on the user's device and the IM server when the IM client is instantiated and the user's device is online. On a conventional computing device, the power used to process periodic presence handshaking is not particularly significant, but for mobile communication devices it can be substantial because such devices have much smaller batteries and are expected to operate for longer periods of time without having to recharge or change batteries compared to computing devices. Furthermore, in an enterprise WLAN, the presence handshaking can consume a substantial portion of network capacity.
Accordingly, there is a need for a means by which presence information can be maintained in a network which reduces the processing burden on terminal devices, such as mobile communication devices, and which reduces network handshaking traffic over conventional presence systems.
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The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.